This is a thesis for a Bachelor Degree Project, performed in the subject MechanicalEngineering. The students Roger Malmberg and Simon Hagberg have carried out adesign project on behalf of the recently established company J&D Assisting systems,located in Halmstad.The project consisted in developing J&D's first prototype of a power assisting solutionfor wheelchairs. A power assisted wheelchair combines human power, which is deliveredby the arms through the pushrims, with electrical motors, which are powered by a battery.The power assisted wheelchair is aimed at customers, who have used a regularwheelchair for a long time, but who have become weaker or just need additional powerwhen driving uphill. This kind of wheelchair will provide additional power for users,which will spare their wrists, elbow and shoulders. The product is Torque sensor free andinstead it relies on the velocity.

Researchers at Karlstad University have developed a method for making paper ion conducting. The reasearchers want to test this technique in various applications and produce products that make use of the ion-conducting paper. Hopefully this will drive the development forward and result in new applications for the ion-conducting paper.This study was to test the possibility of manufacturing a gas sensor of conducting paper along with electrodes of conductive polymers printed on the paper. By comparing the paper sensor with an electrochemical cell in which the electrodes of conductive polymer replaces electrodes of metal and ion-conductive paper replaces the liquid electrolyte in the electrochemical cell, it was hoped that it would be possible to measure the oxidation and reduction reactions that a gas could introduce at the electrodes.It was shown that it is possible to measure a potential difference in the range of 0.3 V to 0.5 V between the electrodes when exposing an electrode to 100% oxygen. The reaction that takes place is relatively slow and the reaction rate is partly due to the distance between the electrodes.Since the sensor can measure oxidation and reduction reactions it is possible that, in further development of a sensor, the sensor can be made ??into a versatile sensor with more applications than gas measurement as there are many more ways to oxidize or reduce the electrodes than by exposure to oxygen.During the study there have been discussions and meetings held with various companies in the sensor industry to be able to specify what the market demands of a sensor made ??of paper and the requirements that must be placed on the sensor for it to be interesting for the companies..

Lansen Technology is a security company from Halmstad, Sweden and their focus indeveloping and selling alarm solutions. One of their latest inventions is a vibration sensor thatrecognizes very small movements in the ground.The thesis work was made in cooperation with Lansen Technology AB and the task was toinvent a test equipment that decides whether the sensor is working correctly. By generatingcertain frequencies with specific amplitude, we will expect the sensor to give a similar output.The final report includes all the parts of our work as studying, choosing components,programming, construction, results and conclusion..

This report reflects an examination work performed for Getrag All Wheel Drive AB during the spring of 2005. Among the companies range of products there exists some concern regarding the amount of clamping force and friction on bolted joints caused by the assembly torque.The aim of this project has been to determine if there is a simple way in which to identify and then practically apply testing methods for clamping force and friction through utilization of existing testing equipment.Three separate methods of clamping force and friction determination have been tested in rear drive unit, RDU, at a 30 Nm assembly torque. A fourth and final method, screw elongation with ultrasound, has been used as reference. The methods are:?Torque-Tension test.?Screw elongation with micrometer.?Joint stiffness test.?Screw elongation with ultra sound for reference.The results from tests can be viewed in table below.MethodTorque-TensionMicrometerCs=318 kN/mm Assembled with torque wrenchMicrometerCs=318 kN/mm Assembled on lineUltra-soundCS=311 kN/mm Ultra- soundCS=318 kN/mm Joint stiffnessTheoreticalClamping force-21,8 kN17,6 kN17,3 kN17,6 kN17,1 kN17,3 kNFriction-0,110,1470,1530,1470,1520,149.

A cars powertrain consists of everything that is needed for its propulsion. The components in the driveline that transfer the power from the engine to the driven wheels are not absolutely stiff, hence they will wind up due to the torque and act as torsion springs. If you suddenly demand a bigger torque by stepping on the accelerator pedal, a so called tip in manoeuvre, and that torque is acquired from the engine as quickly as possible, the driveline will not be able to transfer that fast torque change due to its weakness and as a result it will start to oscillate. These oscillations will be transferred to the driven wheels and make the car to accelerate jerkily which will be experienced as uncomfortable by the passengers. Furthermore, there is a backlash in the driveline that will make the weakness in the driveline even more excited than it should have been if the backlash did not existed.To avoid too big problems with these oscillations there is a control system that controls the demanded torque.

Active sensors are used a lot in the society and industry, for example to gain better control over processes or to get proximity sensing features in different products. Within industry there is great interest in developing safe automation products that can be controlled with high accuracy but still at a low cost.The goal of this project is to develop a prototype of a non-contact rangefinder that measures distance using infrared light. The sensor is to be used for various applications in industries with relatively high accuracy and be compact, but at a low cost. By implementing a rangefinder into a product, more accurate detections of an object?s presence can be done.In this project a new distance sensor, EPC600 from ESPROS, was used.

Today?s system to measure the volume in a tank consists of a vertically placed sensor. When a vehicle is tilted the level of the fluid might change and if the volume is calculated based only on the information from the sensor it could result in a incorrect value.This thesis exams a new method to calculate the volume in tanks by using sensor fusion to crosscheck the i formation from the level sensors when the vehicle is tilted. The information is then used to see if it is possible to identify the grade of tilt by the change of fluid level. If the grade of tilt can be measured then the volume can be calculated in a more accurate way.

The purpose of this thesis is to investigate the possibility to make small, cheap and ultra low power sensor platforms, connected in wireless networks for monitoring of home and industrial environments. The concept is based on ideas from our supervisor, Jerry Lindblom. The developed system consists of a generic platform for different sensors, a receiver and software. A GPRS module from RO Rollytech AB and a database from Gema Industri AB have been modified and used to demonstrate an example of a complete system. To the platform, it is possible to connect any resistive sensor and any sensor that can act as a switch.

Electronic article surveillance (EAS) is widely used in shops and libraries together with an RF-tag attached to the goods or books in order to prevent shoplifting. By implementing the addition of a moisture sensor to the RF-tag, other functions become possible, including the ability to use as an alarm with regards to frozen goods, which have been shipped but which have melted and have, subsequently, refrozen. In- relation to care for the elderly, one time-consuming step involves checking whether there is the necessity for a change of diaper and this can, instead, be based on an RF-tag with an EAS-system alarm. A preliminary investigation was made using the moisture sensors, which involved how the resistance changes when liquid and/or heat is applied. A simulation of the LCCR circuit (RF-tag with the sensor) was conducted in order to determine how the resonance frequency changes for different resistances levels.

This report shows the process of the development of a sensor module for the seed drills of Väderstad Verken AB. The module is supposed to replace existing solutions, provided that it is better from both a constructional- and an economical aspect. The purpose of the sensor is to continuously give the driver information about the level of height of the front- and drilling tools and the main purpose of the sensor is to allow the seeds to be placed at the desired depth. The sensors which have been taken into consideration have all been of an analogue type and have a protection class of minimum IP67.The methods applied have been taken from the book ?The Mechanical Design Process? by David G.

As a leisure time pedagogue I find it hard to have an insight into what children are playing, and how they play when it comes to free play. My experience is that in some free play, conflicts arise, which reveal hierarchies and power structures containing violations, whereas other occasions of free play suddenly come to an end as the pedagogue interferes. In this essay I investigate my responsibility as a leisure time pedagogue during children´s free play, based on two differing play situations. I also investigate the play as a phenomenon by looking into previous research on children?s play and development psychology.

Halleffektsensorn är en magnetisk sensor som används till olika applikationer. Den fungerar bara när ett magnetiskt fält eller en elektrisk ström finns i närheten. Detta arbete är fokuserat på en specifik sensor men beskriver även hur en Halleffektsensor generellt är uppbyggd. Den specifika sensorn används till avståndsmätning. En rad olika tester har utförts för att försöka öka det avstånd som sensorn kan detektera..

Halleffektsensorn är en magnetisk sensor som används till olika applikationer. Den fungerar bara när ett magnetiskt fält eller en elektrisk ström finns i närheten. Detta arbete är fokuserat på en specifik sensor men beskriver även hur en Halleffektsensor generellt är uppbyggd. Den specifika sensorn används till avståndsmätning. En rad olika tester har utförts för att försöka öka det avstånd som sensorn kan detektera..

This work is an experimental study where knock sensor placements are investigated using engine tests. The aim is to studythe quality of the signal from knock sensors and how the signal for engine control is affected at different sensor locations on Scanias, engine DC13. To find out at witch position on the engine youcan get a usable signal for engine control, the engine is running while the knock sensors with advanced measurement equipment is connected to the engine. Evaluation of signals from the knock sensors are made in the computer program Matlab. The program is producing a seriesof plots, from these plots it is visually possible to draw conclusions and find connections.

In this empirical study I have investigated how preschool teachers relate to the free play at the preschool. At the same time I have investigated how the free play is adapted into everyday practice in the preschool. Previous research shows that children process what they experienced in the free play. The child retrieves content to play with through things they have experienced, such as family life, preschool and so on. To play, grow and continue, it is important that free play may take place and space in the daily activities at the preschool.